Persisters Lab Page

Division tracking Results

Recommended/Optional Reading:

Evolution of the lag phase

ScanLag method paper

How a Toxin-Antitoxin system affects the lag

Useful tools and software:

Lab book:

28/07/2014

We set out to quantify the effect of the initial population size on optical density (OD) measurements. To do this, we start with three different strains taken out of the freezer at -80C and grown to stationary phase:

• E. coli MGY:
• E. coli MGHY:
• E. coli 5H:

We carried out fold-dilutions of 1:10^2, 1:10^3, 1:10^4 and 1:10^5.

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29/07/2014

The overnight culture from 28/07 was not measured due to a computer shutdown.

Measurement of colony-forming units (CFUs)

Ofer prepared the three strains, left to grow overnight on 28/07

Strains	CFU	Population size
MGY	419	4.19x109
MGHY	167	1.67x109
5H	262	2.62x109

Calibration of plate reader

Starting with a frozen culture at stationary phase, we do fold dilutions:

Population size	1x109	5x108	2.5x108	1.25x108	6.25x106	3.125x106
Optical density (OD)

To calibrate OD,
$\mathrm{OD} = 1.45\times 10^{-10}\times(\mathrm{no.\,of\,cells})+ 3.9\times 10^{-3}$



We left overnight cultures growing to measure lag times in the scanner.

WT ST	WT ST	5H ST
WT EX	WT EX	5H EX

5H ST	5H ST	WT ST
5H EX	5H EX	WT EX

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30/07/2014

Tecan Growth experiment results

Program for analysis from the Tecan

A little program for looking at Tecan data, can surely be improved.

Fitted values can be read out with via the variables: a_values and b_values

matlab code that analyzes divisions.cvs from ilastik 1.1